Field
The present invention relates to an imprinting method for forming a pattern in an imprint material deposited on a substrate using a mold having the pattern formed thereon, an imprinting apparatus, and a device manufacturing method.
Description of the Related Art
To manufacture, for example, semiconductor devices, imprinting technology has been developed. Imprinting technology (an imprinting method) is used to form a pattern in an imprint material (a resin material) deposited on a substrate using a mold having the pattern formed thereon. In the imprinting technology, a mold (a mask) having a pattern formed therein using, for example, electron beam lithography equipment is in contact with the imprint material deposited on the substrate (i.e., imprinting). Thereafter, the imprint material is cured with the mold in contact with the imprint material. Subsequently, by increasing the distance between the cured imprint material and the mold (releasing), the pattern can be formed in the imprint material.
In some cases, a plurality of shot areas are formed in the substrate that is carried into an imprinting apparatus. In such cases, the pattern is transferred to each of the shot areas using the above-described imprinting method. After the pattern is transferred to all of the shot areas, the substrate is carried out of the imprinting apparatus.
The substrate that is carried into the imprinting apparatus is held by a substrate holding unit. In general, the substrate holding unit attracts the entire back surface (the entire back area) of the substrate so as to hold the substrate. In contrast, like a substrate holding unit described in Japanese Patent Laid-Open No. 2010-098310, a substrate holding unit has an attraction area partitioned into a plurality of sub-attraction areas.
In addition, as in a substrate holding unit described in Japanese Patent Laid-Open No. 2012-234913, a technology for reducing the occurrence of fall of the pattern in resin when the mold is released has been developed. In this technology, the attraction forces of attraction areas for attracting a portion of the back surface of the substrate corresponding to a shot area to which the pattern is transferred and shot areas in the vicinity are decreased. Thereafter, the mold is released.
Japanese Patent Laid-Open No. 2012-234913 describes a technique for transferring a pattern to the shot areas that are not adjacent to each other so as to avoid the influence of the strain of the substrate. When the pattern is transferred to the shot areas corresponding to different attraction areas, the attraction force of the attraction area used for transferring the pattern is increased (returned) to an original strength. In addition, the attraction forces of the different attraction areas are reduced. Accordingly, when the attraction forces of the attraction areas are changed, strain is induced in the substrate. Thus, the position of the shot area to which the pattern is transferred and which corresponds to the attraction area having a reduced attraction force may be displaced from the original position.
When global alignment that is widely used in lithography apparatuses is performed and if the position of the shot area is displaced relative to the original position due to the above-described strain, the positioning accuracy is reduced.